The present invention relates to a drain system for a charge air cooler for an engine.
Charge air coolers are used with engines to cool air compressed by a turbo-compressor. In the process of cooling the air, moisture (water) can condense from the air and collect in the charge air cooler. The condensed liquid water can be drawn into the engine, thus causing engine component corrosion. The water in the charge air cooler can freeze and crack the charge air cooler when the engine is off when the temperature is low. A hydraulic lock may result if significant amounts of liquid enter the engine.
One solution is to bleed liquid condensation from the charge air cooler using of a valve in the bottom of the cooler. This has been done on production John Deere marine engines which operate in high humidity conditions which cause condensation. The valve allows water to exit the cooler when the pressure in the cooler is low, such as when the engine under low load, is idle or is off.
However, such a valve cannot be used in off-road vehicle applications because the air in the off-road environment has high concentrations of dust. This dust, if allowed to enter the charge air cooler in low boost pressure situations would damage the engine. Low engine load can lead to low turbocharger boost pressure. In the charge air cooler, the actual pressure may be a vacuum under these conditions similar to the intake manifold vacuum of a naturally aspirated engine. In such situations, an open pathway from the environment into the charge air cooler would allow dirty air directly into the engine (by-passing the air cleaner).
Future engines will be designed for off-road vehicles and to meet Tier 3 emission regulations. Such engines will have higher compression producing higher temperature rises and thermal loads on the charge air cooler. This, combined with lower outlet temperature requirements will aggravate condensation problems for off-road vehicles like John Deere tractors.